There are many "natural vision correction" systems. Most revolve around the Bates Method of eye exercises. There is no accepted scientific evidence that these systems will do more than accommodate around a very small refractive error.

Orthokeratology (Ortho-K) is a system of hard contact lenses that reshape the cornea to reduce the need for corrective lenses. In some case you can wear the hard contact lenses at night and not need lenses during the day. Ortho-K is most successful for small refractive errors and the effects do dissipate.

Couple of years back I did use the natural correction system to correct my eye power which went down quite a bit during the time I followed it (roughly a week). However, the exercises had to be dome like 4 hrs every day. I don't have that kind of time. My Myopia came back with a vengeance. It was worse than before